Oral fluid, a substitute for serum to monitor measles IgG antibody?

We have analyzed the suitability and potential of Oral Fluid (OF) to substitute serum in estimating measles IgG antibodies, during community surveys, by comparing the Optical Density (OD) of measles IgG antibodies in OF and serum of 100 apparently asymptomatic children. IgG antibody status was determined using commercially available - Measles IgG Capture ELISA. Sensitivity 89.5%, specificity 90.6% Concordance of 89%, coefficient of correlation r is equal to 0.97 (Karl Pearson's) and rho is equal to 0.86 (Spearman's), was found between OD value of OF and serum. The study emphasizes the potential of OF to surrogate serum in estimating Measles IgG antibody among children. The OF collection is advantageous over blood as it is painless. It is suitable for non-technical staff, easy to transport and less bio-hazardous.